Invalid Cast Exception When Assigning A Parent To A Child Type?
Nov 2, 2009
I've created a class that inherits from Dictionary(Of TKey, TValue) called KeyCopyDictionary(Of TKey, TValue). I'm now trying to use a pre-existing function which returns a Dictionary(Of String, String) and assigning it to a variable of type KeyCopyDictionary(Of String, String). I'm getting an invalid cast exception. Is it not possible to assign a variable of a parent type to a variable of its child type? I've tried DirectCast and CType to no avail on this...
i know this may seam odd but I'm getting an error navigating through a datagrid of an invalid cast. The trouble is it is of the same types!! I working on customising some Sage code and in the form there is a datagrid that is populated by a series of Sage.Accounting.Stock.TraceableSOPAllocationItems (a batched stock item allocated to an SOP).
I want to give the user some further information on each item so they can decide which batch and bin to use. I want to go through each item in the grid and then go find this extra information for it. the trouble is when I go to navigate through, My VB.Net code throws the error.InvalidCastException was unhandled by user code, Unable to cast object of type 'Sage.Accounting.Stock.TraceableSOPAllocationItem' to type 'Sage.Accounting.Stock.TraceableSOPAllocationItem'.
I'm using WMI code and VB 2008 to see NIC status. So far the queries are working, but the methods aren't. For example, I'm trying to set a network card to use DHCP, I get invalid function with this code:
Dim classInstance As New ManagementObject("rootCIMV2", "Win32_NetworkAdapterConfiguration.Index='7'", Nothing) Dim outParams As ManagementBaseObject = classInstance.InvokeMethod("EnableDHCP", Nothing, Nothing)
see from the following function why I would be getting an "Invalid Cast Exception"? More specifically this is the error "Conversion from string "yyyyMMdd" to type 'Integer' is not valid." I am trying to convert a DateTime value from the database to a String with the format "yyyyMMdd" so for example October 22, 1985 would be "19851022".dbReader(fieldName).ToString("yyyyMMdd")Here is the entire function ...
Private Function GetDBReaderDateValue(ByVal dbReader As IDataReader, ByVal fieldName As String) As String If dbReader(fieldName) Is DBNull.Value Then
I'm trying to make a card game where the user chooses either Clubs, Hearts, Spades, Diamonds or Joker and then the computer randomly chooses a card to counter and then depending on the formula of what beats what the scores are tallied.
Here is the:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[CODE]...
Now I pick a card and the computer picks a card and it displays the winner but then immediately it sends me to the coding highlighting lblcomp.text += Val(0.5,1, or 4) saying "Invalid Cast Exception was Unhandled" "Conversion from string "" to type 'Double' is not valid.
I've seen some other responses about this and they talk about interfaces but I'm pretty sure you can do this with classes and base classes but I can't this to work.[code]....When it tries to convert whatever Activator.CreateInstance(t) returns to the base class of type Behavior I'm getting invalid cast exception. That type should be of CharacterController which is defined as a child of Behavior so why wouldn't it let me cast that?
I am getting Invalid Cast Exception was unhandled.Conversion from String 'abc' to type 'Double' is not valid in the following line!
If ((xlBook.Worksheets(2).Cells(iRowIndex, iColumnIndex).Value)) = avFoundKeywordds(iSearchText) Then
The business intent is that user enters the keyword 'abc' and clicks search button . We have defined different keywords in a xls which has 1600 rows and 16 columns . so when finding abc in any of the cells ,it has to return the value of a column#4 where the name is specified !
i save image into a database correctly and now when it come to retrieving i get an error message when the photograph column is NULL.Is there any way i can check if it is null then i execute different code else it return the image.This is what i am using for now
Dim barrImg() As Byte Dim cmdSelect As New SqlCommand("select Photograph from Personal where MyID=@ID", connect)
We are trying to implement a logic which we used in vb6 2 years back.User enters a business requirement in text box, we define the keywors in the script and once the button is clicked , it shld luk from the list and display a msgbox of number of keywrods found.
1. Invalid Cast Exception was unhandled error -->Warnings
2.When casting from a number , the value must be a number less than infinity -->Warnings
3.When trying to declare ,variant is not accepting and its converting it into Variant Type. Are these both same?[code]
I have declared two variables as strings strDob and strCurrentDate, Both Variables are for storing dates. StrDob is for storing Date of Birth and second is for Present date. and am executing the following code
If DateValue(strDOB) > DateValue(Date.Today) Then and getting the error like Invalid CastException was unhandled Conversion from string "19/09/1987" to type 'Date' is not valid.
Error in the following code also: iAge = (CInt(Abs(DateDiff("d", strCurrentDate, strDOB)) / 365)) Invalid CastException was unhandled Argument 'Date1' cannot be converted to type 'Date'. Here I need both variables as string itself. because the Dateofbirth is getting from three comboboxes.
textbox1.text = "6916092, 15195440, 16107657, 1836924, 3758726, 12566463, 7526079, 7405793, 6945974, 241502, 2296476, 5130294, 3102017, 7324121, 14993507" ColorDialog1.CustomColors = New Integer() {TextBox1.Text} I am getting an InvalidCastException. How do I insert the value of textbox1.text into those brackets in vb.net?
I've got a masked text box that throws an invalid cast exception if I try to put anything in the TextChanged event: Private Sub mtbZVal_TextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MaskInputRejectedEventArgs) Handles mtbZVal.TextChanged MsgBox("OK!") End Sub
Even more oddly, it throws the exception in a completely different part of the program. The masked textbox is on a form that opens when you press a button, and that's the bit that gives the error: Private Sub cmdAddLoc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdAddLoc.Click If frmLocation.ShowDialog() = DialogResult.OK Then End If End Sub
I'm just converting a date to a string but I'm getting this error. It's not listed as one of the normal exceptions to the datetime.tostring method. Googling around, it looks like it's an actual bug where it thinks StartDate is an int--but that's no help to me, as I just need to convert the date.
dim StartDate as nullable(of date) dim Date1 as string if not StartDate is nothing then Date1 = StartDate.tostring("yyyy-mm-dd") end if
I am using VB.NET 2010 (Visual Basic 2010 Express) on a WPF-based project. I am also using the SQL Server Express built-in to Visual Basic 2010 express.I have just about finished refining my code for hooking up my wpf-based form to an existing SQL database (agentroster.sdf). I have a global data source (AGENT_ROSTER) connected to this database. Connections are confirmed to work properly.This is the first part of the code I'm using, irrelevant code omitted,
Dim table_adaptor As New AGENT_ROSTERTableAdaptors.AGENT_ROSTERTableAdaptor Dim roster_table As New DataTable("roster_table") Dim rowposition As Integer
[code]....
how do I fill roster_table with table_adaptor (or alternate method)?
As you can see, I've defined the NullValue to be zero, yet I get an InvalidCastException. Is there anything I'm doing wrong? Or is handling the binding's Format and Parse events the only way around this?
Ok, just needing a 2nd set of eyes looking at this to make sure the error isn't something else other than my LINQ code here. Here's the function class itself:
Public Function GetJacketByPolicyID(ByVal jacketID As Int32) As tblPolicy Dim db As New DEVDataContext() Dim j As tblPolicy = db.tblPolicies.Single(Function(p) p.policyNumber = jacketID) Return j End Function
and here is the code which calls this class function in the web control form itself:
Dim p As tblPolicy Dim j As New Jackets() p = j.GetJacketByPolicyID(3000050)
For some reason it's flagging the 2nd line in the GetJacketByPolicyID function saying the specified cast is not valid. So I'm guessing it's something I'm doing wrong. I'm sure the tblPolicy/tblPolicies class works right since I can create a new instance of a tblPolicy and set a few variables by hand and return it, so that's not it. I've also checked the datarow I'm fetching and there's no null values in the record, so that shouldn't be it either.
I have below program that throw exception. Do you know how to fix??
Dim conn As New SqlCeConnection
conn.ConnectionString = "Data Source=" & Dir & StockTakeFile & ";Persist Security Info=False" conn.Open() Dim cmd As New SqlCeCommand("select * from TableStockTake", conn) Dim reader As SqlCeDataReader reader = cmd.ExecuteReader()
When testing the followng code from Mastering VB2010, I get an Unable to cast object of type 'System.String' to type 'System.IFormatProvider' exception.In the Button1_Click event code Dim strmOut As New System.IO.StringWriter(SaveFileDialog1.FileName)the 'SaveFileDialog1. FileName' is underlined with a green squiggle and displays the following tool tip:Runtime errors might occur when converting 'String' to'System. Iformat Provider'.This is apparrently the problem but what does it mean and how do I fix it to get the code to work? 'Code being tested that runs the exception:Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click.[code]
I had a working program a while ago, but now it is giving me an error when I try to insert some data to my Excel-file.I get this error: Old format or invalid type library. (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD)) For example, one of my Excel referencing codes is:
Dim XL_App As New Excel.Application Dim XL_WB As Excel.Workbook = XL_App.Workbooks.Open("C:Program FilesIAAExcelitTuntilappu.xls", , True) Dim XL_WS1 As Excel.Worksheet = XL_WB.Worksheets(1)
The above code used to work, but now it gives me the error...I recently updated my Office from 2003 to 2010. How can I fix it?
Im working with MDI parent/child objects. when closing the child objects i need the child to check to see if it is the last child object before closing. i couldn't find anything on google, maybe im searching for the wrong thing.
VB 2003 Combobox collection from -3 to +3 The goal of the message is to warn the user that the systems only covers +- 3 timezones, if he types in for example +4 or -4, he gets the message (by the way: how to protect the system if he types for instance a character?)
When I run the application: 'Unhandled exception: Cast from string "click" to type 'integer' is not valid
Private Sub ComboBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.TextChanged
Combobox collection from -3 to +3 The goal of the message is to warn the user that the systems only covers +- 3 timezones, if he types in for example +4 or -4, he gets the message (by the way: how to protect the system if he types for instance a character?)
When I run the application: 'Unhandled exception: Cast from string "click" to type 'integer' is not valid
Private Sub ComboBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs)